Ebullient cooling device

ABSTRACT

A power card is accommodated in a vaporizing portion. Heat medium in the vaporizing portion is vaporized by heat generated at the power card so as to cool down the power card. A vapor passage and a condensing portion are connected to the vaporizing portion and a communication passage is provided at upper ends of the vapor passage and the condensing portion. The heat medium vaporized in the vaporizing portion moves up to the communication passage and to the condensing portion, so that the heat medium is condensed in the condensing portion and moves to the vaporizing portion. The condensing portion is arranged at an upstream side of the vapor passage in a direction of blowing air. A cross sectional area of the vapor passage is larger than that of the condensing portion.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2012-078763 filed on Mar. 30, 2012, the disclosure of which is incorporated herein by reference.

FIELD OF TECHNOLOGY

The present disclosure relates to an ebullient cooling device, which brings heat medium to a boil by heat generated at an electronic component to be cooled down (a cooling object) in order to absorb the heat from the cooling object and thereby to cool down the cooling object.

BACKGROUND

An ebullient cooling device is known in the art, for example, as disclosed in Japanese Patent No. 3487382. The ebullient cooling device has a heat-medium portion for accommodating heat medium therein, a cooling object (an electronic device) attached to and brought into contact with an outer wall surface of the heat-medium portion, and a heat radiating portion provided at an upper side of the heat-medium portion and communicated to the heat-medium portion in order to carry out heat exchange between ambient air and the heat medium rising up from the heat-medium portion so that the heat medium is cooled down and liquefied.

According to the above ebullient cooling device, a vapor moving-up passage, through which heat medium vaporized in the heat-medium portion passes, and a vapor moving-down passage, through which the heat medium condensed by heat exchange with the ambient air passes, are not clearly separated from each other. As a result, it is a disadvantage of the prior art ebullient cooling device, in that liquid-phase heat medium which is condensed by the heat exchange with the air and moves in a downward direction may prevent the heat medium vaporized in the heat-medium portion from moving in an upward direction. Then, sufficient circulation of the heat medium cannot be carried out and thereby necessary cooling performance of the ebullient cooling device cannot be obtained.

SUMMARY OF THE DISCLOSURE

The present disclosure is made in view of the above point. It is an object of the present disclosure to provide an ebullient cooling device which can improve its cooling performance.

According to a feature of the present disclosure, an ebullient cooling device has;

a cooling object;

a vaporizing portion for cooling down the cooling object by vaporizing heat medium through heat exchange between the cooling object and the heat medium;

a condensing portion for condensing the heat medium through heat exchange between the heat medium and outside fluid, to thereby radiate heat of the heat medium to the outside fluid; and

a vapor passage for moving the heat medium vaporized in the vaporizing portion to the condensing portion.

In the above ebullient cooling device,

the condensing portion moves the heat medium condensed in the condensing portion to the vaporizing portion,

the condensing portion and the vapor passage are so arranged to overlap with each other in a direction of flow of the outside fluid,

the condensing portion is arranged at an upstream side of the vapor passage in the direction of the flow of the outside fluid, and

a cross sectional area of the vapor passage is larger than that of the condensing portion.

According to the above feature, since the cross sectional area of the vapor passage is larger than that of the condensing portion, pressure loss of the heat medium in the vapor passage can be reduced, to thereby improve circulation performance of the heat medium. Accordingly, the cooling performance of the ebullient cooling device can be increased.

According to another feature of the present disclosure, an ebullient cooling device has;

a cooling object;

a vaporizing portion for cooling down the cooling object by vaporizing heat medium through heat exchange between the cooling object and the heat medium;

a condensing portion for condensing the heat medium through heat exchange between the heat medium and outside fluid, to thereby radiate heat of the heat medium to the outside fluid; and

a vapor passage for moving the heat medium vaporized in the vaporizing portion to the condensing portion.

In the above ebullient cooling device,

the condensing portion moves the heat medium condensed in the condensing portion to the vaporizing portion,

the condensing portion and the vapor passage are so arranged to overlap with each other in a direction of flow of the outside fluid, and

the condensing portion is arranged at an upstream side of the vapor passage in the direction of the flow of the outside fluid.

In addition, the ebullient cooling device has multiple fluid-passage plate units, each of which has the condensing portion, the vapor passage and a communication passage for communicating the condensing portion and the vapor passage with each other,

the multiple fluid-passage plate units are built up in a plate built-up direction, and

the communication passages of the neighboring fluid-passage plate units are communicated to each other.

According to the above feature, since the communication passages of the neighboring fluid-passage plate units are communicated to each other, it is possible to equally distribute the heat medium to the respective condensing portions via the communication passages, even when an amount of the heat medium become imbalanced in the vapor passages. As a result, it becomes possible to condense the heat medium in all of the condensing portions. The whole area of the ebullient cooling device can be thus effectively used to thereby increase the cooling performance of the ebullient cooling device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic front view showing an ebullient cooling device according to an embodiment of the present disclosure;

FIG. 2 is a schematic cross sectional view taken along a line II-II in FIG. 1;

FIG. 3 is a schematic cross sectional view taken along a line in FIG. 2; and

FIG. 4 is a schematic cross sectional view taken along a line IV-IV in FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An ebullient cooling device according to an embodiment of the present disclosure will be explained with reference to FIGS. 1 to 4. The ebullient cooling device is mounted in a vehicle. An arrow Up-Down shown in each drawing indicates a vertical direction, when the ebullient cooling device is mounted in the vehicle.

As shown in FIGS. 1 and 2, the ebullient cooling device of the present embodiment is composed of a vaporizing portion 1 and a core portion 3 having a condensing portion 2. The vaporizing portion 1 corresponds to a heat exchanger, according to which heat medium is vaporized through heat exchange between a power card 100 and the heat medium to thereby cool down the power card 100. The power card 100 is an electronic component corresponding to a cooling object, which is cooled down by the ebullient cooling device. The condensing portion 2 corresponds to another heat exchanger, at which the heat medium vaporized at the vaporizing portion 1 is condensed so that heat of the heat medium is radiated to blowing air. Water, alcohol or the like, which can be vaporized and condensed, is used as working fluid for the heat medium.

The vaporizing portion 1 is formed in a container shape for storing the liquid-phase heat medium in its inside space. A partitioning member 11 is provided in the inside space of the vaporizing portion 1 for dividing the inside space into two sub-spaces, that is, a first sub-space 1 a and a second sub-space 1 b. The partitioning member 11 extends from an upper-side wall of the vaporizing portion 1 toward a lower-side wall (a bottom wall) in a vertical direction.

An upper-side end of the partitioning member 11 is connected to the upper-side wall of the vaporizing portion 1. A lower-side end of the partitioning member 11 is not connected to the bottom wall of the vaporizing portion 1 but separated therefrom by a certain distance, so that the first and the second sub-spaces 1 a and 1 b are communicated to each other through a space formed between the lower-side end of the partitioning member 11 and the bottom wall of the vaporizing portion 1. In the present embodiment, the first sub-space 1 a is made larger than the second sub-space 1 b. The power card 100 is accommodated in the first sub-space 1 a. An opening 12 is formed in the upper-side wall of the vaporizing portion 1. As explained below, a lower-side end of a fluid-passage plate unit 31 of the core portion 3 is inserted into the opening 12 and firmly fixed thereto.

The core portion 3 is arranged at an upper side of the vaporizing portion 1. A direction for arranging the vaporizing portion 1 and the core portion 3 coincides with the vertical direction (a direction of gravitational force).

The core portion 3 has multiple fluid-passage plate units 31 and wave-shaped (corrugate-shaped) outer fins 32. The fluid-passage plate units 31 are assembled to the upper side of the vaporizing portion 1, so that each of the fluid-passage plate units 31 extends from the upper side of the vaporizing portion 1 in the vertical and upward direction. Each of the outer fins 32 is arranged between neighboring fluid-passage plate units 31 and fixed to an outer surface of the respective fluid-passage plate units 31. Each of the fluid-passage plate units 31 forms a heat-medium passage therein, so that the heat medium flows in the heat-medium passage. The outer fins 32 increase heat-transfer area between the blowing air (cooling air) from a blower unit 4 and the fluid-passage plate units 32. The blowing air is also referred to as outside fluid.

As shown in FIG. 2, the condensing portion 2, a vapor passage 5 and a communication passage 6 are formed inside of each fluid-passage plate unit 31. The heat medium vaporized in the vaporizing portion 1 flows through the vapor passage 5 in an upward direction to the communication passage 6, which connects the vapor passage 5 to the condensing portion 2. A longitudinal direction of the vapor passage 5 as well as a longitudinal direction of the condensing portion 2 coincides with a direction of gravitational force. The outer fin 32 is provided only at an area of the outer surface of the fluid-passage plate unit 31 corresponding to the condensing portion 2. In other words, the outer fin 32 is not provided at another area of the outer surface of the fluid-passage plate unit 31 corresponding to the vapor passage 5.

The communication passage 6 is arranged at an upper end of the fluid-passage plate unit 31 and communicates an upper end of the condensing portion 2 and an upper end of the vapor passage 5 with each other.

More in detail, a partitioning wall 311 is provided inside of the fluid-passage plate unit 31 in order to divide the inside space into two spaces, that is, an upstream side space (the condensing portion 2) and a downstream side space (the vapor passage 5). The condensing portion 2 and the vapor passage 5 are arranged in this order in a direction of the blowing air indicated by an arrow. A lower end of the partitioning wall 311 provided in the fluid-passage plate unit 31 is connected to the upper end of the partitioning member 31 provided in the vaporizing portion 1. An upper end of the partitioning wall 311 provided in the fluid-passage plate unit 31 is connected to the communication passage 6.

The downstream side space (the vapor passage 5), which is formed in the inside of the fluid-passage plate unit 31 by the partitioning wall 311 and arranged at the downstream side in the direction of the blowing air, is communicated to the first sub-space 1 a of the vaporizing portion 1. The downstream side space forms the vapor passage 5. On the other hand, the upstream side space, which is formed in the inside of the fluid-passage plate unit 31 by the partitioning wall 311 and arranged at the upstream side in the direction of the blowing air, is communicated to the second sub-space 1 b of the vaporizing portion 1. The upstream side space forms the condensing portion 2. As above, the condensing portion 2 and the vapor passage 5 overlap each other in each fluid-passage plate unit 31 when viewed in the direction of the blowing air. And the condensing portion 2 is arranged at the upstream side of the vapor passage 5 in the direction of the blowing air.

According to the present embodiment, a width of a connecting portion 81 in the direction of the blowing air between the first sub-space 1 a of the vaporizing portion 1 and the vapor passage 5 formed in the inside of the fluid-passage plates 31 is made to be larger than that of a connecting portion 82 in the direction of the blowing air between the second sub-space 1 b of the vaporizing portion 1 and the condensing portion 2 formed in the inside of the fluid-passage plate unit 31.

As shown in FIGS. 2 and 3, an inner fin 21 is provided inside of the condensing portion 2 in order to facilitate heat exchange between the blowing air and the heat medium. More in detail, the inner fin 21 has a wave shape in a direction perpendicular to fluid flow of the heat medium in the condensing portion 2. Top portions of the wave-shaped inner fin 21 are fixed to an inner wall of the condensing portion 2, so that the inside space of the condensing portion 2 (a fluid passage for the heat medium) is divided into multiple sub-passages for the heat medium.

As shown in FIG. 4, a width of the communication passage 6 in a plate built-up direction is larger than that of the vapor passage 5 in the plate built-up direction. In other words, a portion of the fluid-passage plate unit 31 for forming the communication passage 6 (hereinafter, a communication-passage forming portion 61) outwardly projects in the plate built-up direction from a portion of the fluid-passage plate unit 31 for forming the vapor passage 5 (hereinafter, a vapor-passage forming portion 51). Namely, the communication-passage forming portion 61 is expanded in the plate built-up direction toward a neighboring fluid-passage plate unit 31.

As shown in FIGS. 3 and 4, a pair of through-holes 62 is formed in the communication-passage forming portion 61 of the fluid-passage plate unit 31, at such portions opposing in the plate built-up direction to the communication-passage forming portions 61 of the neighboring fluid-passage plate units 31. Multiple fluid-passage plate units 31 are built up in the plate built-up direction so that the each of the through-holes 62 of the fluid-passage plate unit 31 overlaps with the through-hole 62 of the neighboring fluid-passage plate unit 31. As a result, the communication passages 6 of the neighboring fluid-passage plate units 31 are communicated to each other.

As shown in FIG. 3, across sectional area of the vapor passage 5 is larger than that of the condensing portion 2. The width of the vapor passage 5 in the plate built-up direction is larger than that of the condensing portion 2 in the plate built-up direction. As a result, a distance between the condensing portions 2 of the neighboring fluid-passage plate units 31 in the plate built-up direction is larger than that between the vapor passages 5 of the neighboring fluid-passage plate units 31 in the plate built-up direction.

A heat insulating member 52 is provided at an outer surface of the vapor-passage forming portion 51 of the fluid-passage plate unit 31 for suppressing heat transfer between the inside and the outside of the vapor passage 5. The heat insulating members 52 are provided at both sides of the vapor passage 5. As a result, a thermal resistance between the vapor passage 5 and the blowing air becomes higher than that between the condensing portion 2 and the blowing air.

As shown in FIG. 4, a pair of reinforcing ribs 312 is provided at the outer surfaces of the vapor-passage forming portion 51 of the fluid-passage plate unit 31. More in detail, each of the reinforcing ribs 312 is provided at the outer surface of the fluid-passage plate unit 31 and has a semi-circular cross sectional shape projecting in the plate built-up direction toward the neighboring fluid-passage plate unit 31. Although not shown in the drawing, a top portion of the reinforcing rib 312 is in contact with a top portion of the other reinforcing rib 312 of the neighboring fluid-passage plate unit 31. The reinforcing rib 312 has a function for improving pressure resistance of the vapor passage 5. As a result, it is possible to avoid a situation that the fluid-passage plate unit 31 is expanded and broken when inner pressure of the fluid-passage plate unit 31 is increased.

According to the present embodiment, the fluid-passage plate unit 31 is composed of a pair of plate members 71 and 72, which are fixed to each other so as to form the heat-medium passages (the condensing portion 2, the vapor passage 5 and the communication passage 6) between the plate members 71 and 72. The plate members 71 and 72 are built up in the plate built-up direction, wherein the outer fin 32 is interposed in each space between the neighboring plate members 71 and 72. As above, the ebullient cooling device of the present embodiment has a drawn-cup structure.

In the ebullient cooling device of the present embodiment, the cross sectional area of the vapor passage 5 is larger than that of the condensing portion 2. Since pressure loss of the heat medium in the vapor passage 5 can be made smaller, it is possible to increase circulating performance of the heat medium. In other words, the cooling performance of the ebullient cooling device can be improved.

In a case of an ebullient cooling device, in which communication passages are not communicated to each other between the neighboring fluid-passage plate units, amount of heat medium may become imbalanced between vapor passages of the respective fluid-passage plate units. More in detail, when the ebullient cooling device is inclined, the heat medium may flow into the vapor passages of only some of the fluid-passage plate units while the heat medium may not flow into the vapor passages of the remaining fluid-passage plate units. As a result, the amount of the heat medium may become imbalanced between the vapor passages of the fluid-passage plate units. In such a case, the heat medium is not condensed in the condensing portion of the fluid-passage plate unit, into which the heat medium does not flow. In other words, all of the fluid-passage plate units cannot be effectively used, and thereby the cooling performance of the ebullient cooling device is decreased.

On the other hand, in the ebullient cooling device of the present embodiment, the communication passages 6 are communicated to each other between the neighboring fluid-passage plate units 31. According to such a structure, even in a case that the amount of the heat medium becomes imbalanced between the vapor passages 5 of the neighboring fluid-passage plate units 31, it is possible to equally distribute via the communication passage 6 the heat medium to each of the condensing portions of the respective fluid-passage plate units 31. As a result, since it becomes possible to condense the heat medium in all of the condensing portions 2 of the fluid-passage plate units 31, the whole portion of the ebullient cooling device can be effectively used to increase the cooling performance thereof.

In addition, according to the ebullient cooling device of the present embodiment, the thermal resistance between the vapor passage 5 and the blowing air is higher than that between the condensing portion 2 and the blowing air. According to such a structure, it is possible to suppress that the heat medium vaporized in the vaporizing portion 1 is condensed in the vapor passage 5. Namely, it is possible to increase the circulating performance of the heat medium, to thereby increase the cooling performance of the ebullient cooling device.

According to the ebullient cooling device of the present embodiment, the communication passage 6 is provided at the upper end of the fluid-passage plate unit 31. According to such a structure, it is possible to condense the heat medium in the whole area of the condensing portion 2 in the vertical direction, to thereby improve the cooling performance of the ebullient cooling device.

Other Embodiments and/or Modifications

The present disclosure should not be limited to the above embodiment, but maybe modified in various manners as below without departing from the spirit of the present disclosure.

(1) In the above embodiment, the fluid-passage plate unit 31 is composed of the pair of the plate members 71 and 72, which are fixed to each other to form therein the heat-medium passage. And the multiple fluid-passage plate units 31 are built up to form the core portion 3, which is formed in the drawn-cup structure. However, the structure of the core portion 3 should not be limited to the drawn-cup structure.

For example, a so-called tank-and-tube structure may be used. According to such a structure, a condensing portion and a vapor passage are formed in a tube and multiple tubes are connected to a tank for collecting and distributing heat medium (the tank corresponds to the communication passage 6 of the present disclosure).

(2) In the above embodiment, the power card 100 (the cooling object) is accommodated in the vaporizing portion 1. However, the power card 100 may be provided at an outer wall of the vaporizing portion 1, wherein the power card 100 is thermally connected to the outer wall.

(3) In the above embodiment, the heat insulating member 52 is provided at the outer surface of the vapor passage 5 of the fluid-passage plate unit 31, so that the thermal resistance between the vapor passage 5 and the blowing air becomes higher than that between the condensing portion 2 and the blowing air. However, the vapor-passage forming portion 51 of the fluid-passage plate unit 31 may be made of such material, which has higher heat insulating properties than that for the portion of the fluid-passage plate unit 31 for forming the condensing portion 2. 

What is claimed is:
 1. An ebullient cooling device comprising: a cooling object; a vaporizing portion for cooling down the cooling object by vaporizing heat medium through heat exchange between the cooling object and the heat medium; a condensing portion for condensing the heat medium through heat exchange between the heat medium and outside fluid, to thereby radiate heat of the heat medium to the outside fluid; and a vapor passage for moving the heat medium vaporized in the vaporizing portion to the condensing portion, wherein the ebullient cooling device is characterized in that; the condensing portion moves the heat medium condensed in the condensing portion to the vaporizing portion, the condensing portion and the vapor passage are so arranged to overlap with each other in a direction of flow of the outside fluid, the condensing portion is arranged at an upstream side of the vapor passage in the direction of the flow of the outside fluid, and a cross sectional area of the vapor passage is larger than that of the condensing portion.
 2. The ebullient cooling device according to claim 1, further comprising: multiple fluid-passage plate units, each of which has the condensing portion, the vapor passage and a communication passage for communicating the condensing portion and the vapor passage with each other, wherein the multiple fluid-passage plate units are built up in a plate built-up direction, and wherein a width of a vapor-passage forming portion of the fluid-passage plate unit in the plate built-up direction is larger than a width of a portion of the fluid-passage plate unit for the condensing portion in the plate built-up direction.
 3. The ebullient cooling device according to claim 2, wherein the communication passage is provided at an upper end of the fluid-passage plate unit in a vertical direction.
 4. The ebullient cooling device according to claim 1, further comprising: an outer fin provided at an outer side of the condensing portion so as to facilitate the heat exchange between the heat medium and the outside fluid.
 5. The ebullient cooling device according to claim 1, further comprising: an inner fin provided inside of the condensing portion so as to facilitate the heat exchange between the heat medium and the outside fluid.
 6. The ebullient cooling device according to claim 1, wherein a thermal resistance between the vapor passage and the outside fluid is higher than that between the condensing portion and the outside fluid.
 7. The ebullient cooling device according to claim 1, further comprising: a reinforcing member provided between the neighboring fluid-passage plate units for increasing pressure resistance of the vapor passage.
 8. An ebullient cooling device comprising: a cooling object; a vaporizing portion for cooling down the cooling object by vaporizing heat medium through heat exchange between the cooling object and the heat medium; a condensing portion for condensing the heat medium through heat exchange between the heat medium and outside fluid, to thereby radiate heat of the heat medium to the outside fluid; and a vapor passage for moving the heat medium vaporized in the vaporizing portion to the condensing portion, wherein the ebullient cooling device is characterized in that; the condensing portion moves the heat medium condensed in the condensing portion to the vaporizing portion, the condensing portion and the vapor passage are so arranged to overlap with each other in a direction of flow of the outside fluid, the condensing portion is arranged at an upstream side of the vapor passage in the direction of the flow of the outside fluid, the ebullient cooling device further comprises multiple fluid-passage plate units, each of which has the condensing portion, the vapor passage and a communication passage for communicating the condensing portion and the vapor passage with each other, the multiple fluid-passage plate units are built up in a plate built-up direction, and the communication passages of the neighboring fluid-passage plate units are communicated to each other.
 9. The ebullient cooling device according to claim 8, wherein the communication passage is provided at an upper end of the fluid-passage plate unit in a vertical direction.
 10. The ebullient cooling device according to claim 8, further comprising: an outer fin provided at an outer side of the condensing portion so as to facilitate the heat exchange between the heat medium and the outside fluid.
 11. The ebullient cooling device according to claim 8, further comprising: an inner fin provided inside of the condensing portion so as to facilitate the heat exchange between the heat medium and the outside fluid.
 12. The ebullient cooling device according to claim 8, wherein a thermal resistance between the vapor passage and the outside fluid is higher than that between the condensing portion and the outside fluid.
 13. The ebullient cooling device according to claim 8, further comprising: a reinforcing member provided between the neighboring fluid-passage plate units for increasing pressure resistance of the vapor passage.
 14. An ebullient cooling device comprising: a vaporizing portion filled with working fluid; a partitioning member provided in the vaporizing portion for dividing an inside space of the vaporizing portion into a first sub-space and a second sub-space; an electronic device accommodated in the first sub-space, so that the electronic device is cooled down by vaporizing the working fluid in the first sub-space; and a core portion provided at an upper side of the vaporizing portion and having multiple fluid-passage plate units, wherein each of the fluid-passage plate units comprises; a pair of plate members fixed to each other to form therein a fluid passage; a partitioning wall for diving an inside space formed between the pair of the plate members into an upstream side space and a downstream side space; and a communication passage formed at an upper portion of the inside space formed between the pair of the plate members so as to communicate the upstream side and the downstream side spaces with each other, wherein a lower end of the downstream side space is connected to the first sub-space of the vaporizing portion, so that vapor of the working fluid generated in the first sub-space moves up through the downstream side space to the communication passage, and wherein a lower end of the upstream side space is connected to the second sub-space of the vaporizing portion, so that the working fluid flows from the communication passage to the second sub-space through the upstream side space. 